Abstract: A fireplace heating unit apparatus for insertion into a fireplace and hearth arrangement having two parallel heat exchange units forming a fireplace grate with each unit including a series of hollow tubing heat exchange members having a plurality of zigzag air passages therein, an air intake and a blower arrangement for directing heating air through both of the units, and in which the air intake receives air from an air space substantially vertically beneath the fireplace and hearth location. Also provided is an air gap or auxiliary air intake located proximate the blower for admitting air to be heated from the air space proximate the fireplace and hearth and for mixing this air with the air drawn from the lower air space.